1. Field of the Invention
Apparatuses consistent with the present invention relate to a ferroelectric hard disk device and, more particularly, to a ferroelectric hard disk device in which a hard disk media is formed to include a ferroelectric body to store and reproduce information using the switching principle of a ferroelectric dipole.
2. Description of the Related Art
With industrialization and the proliferation of information, the amount of information a person or an organization processes is increasing rapidly. Computers, which can be used to access the internet to get a wide range of information, and which have high data processing speeds and large data capacities are already widely used. In order to increase the data processing speed of the computers, CPU chips and computer peripheral appliances have been improved. Also, in order to improve data storage capacities, high densification for various kinds of information storage mediums, for example, hard disk drives, is being attempted.
A hard disk drive (HDD) device, one kind of information storage medium, usually includes a round-shaped disk type media with a magnetic layer on which a magnetic head for writing and reading information is formed. The magnetic head is installed in a suspension formed at an end of a swing arm, and is moved to desired track position on the media according to the operation of the swing arm to perform writing and reading operations. The magnetic head includes a reading head for outputting information stored in the media and a writing head for storing information. Recently, HDD devices have been developed as perpendicular magnetic recording types from horizontal magnetic recording types to increase the recording densities of information.
FIG. 1 is a cross-sectional view of a recording head and a recording medium of a typical HDD device. Referring to FIG. 1, the typical perpendicular magnetic recording device includes a recording medium 110, a recording head 120 recording data to the recording medium 110, and a reading head 130 for reading the data on the recording medium 110.
The recording medium 110 usually includes a substrate 111, a magnetic recording layer 112 on which information is recorded, and a protection layer 113. The recording head 120 includes a main pole P1, a return pole P2, and a coil C. The main pole P1 and the return pole P2 may be formed of a magnetic material such as nickel iron (NiFe), and here, the component ratio of each material should be different to obtain different coercivities for the main pole P1 and the return pole P2. The main pole P1 and the return pole P2 are used directly to record data to the magnetic recording layer 112 of the perpendicular magnetic recording medium 110. An auxiliary pole 121 is further formed at a side of the main pole P1 so that a magnetic field generated around the main pole P1 during data recording is gathered in a selected region of the perpendicular magnetic recording medium 110. The coil C surrounds the main pole P1 and generates a magnetic field. The reading head 130 includes first and second magnetic shield layers S1 and S2, and a magnetic resistance device 131 formed between the first and second magnetic shield layers S1 and S2. While reading data of a predetermined region of the selected track, the first and second magnetic shield layers S1 and S2 shield any other magnetic fields generated from magnetic elements around the region from arriving at the region being read. The data reading head 130 may be a magnetic resistance device such as a giant magneto resistance (GMR) structure or a tunnel magneto resistance (TMR) structure.
The magnetic resistance devices as described above use a perpendicular magnetic recording method to increase the information storage density; however, it is known that the recording density thereof of is 500-600 Gb/in2 at most. Thus a further improved high density information storage device is required.